Antibody deficiency is a condition where the body does not produce enough antibodies, which are proteins that help fight infections. This can lead to increased susceptibility to infections, particularly from bacteria and viruses. People with antibody deficiency may experience frequent or severe illnesses, requiring medical attention. There are various types of antibody deficiency, including primary immunodeficiency disorders and secondary immunodeficiency disorders. Primary deficiencies are often genetic, while secondary deficiencies can result from factors like medications, malnutrition, or chronic diseases. Diagnosis typically involves blood tests to measure antibody levels and assess immune function.